Blockers are one of the most subtle concepts in advanced poker. They influence which hands your opponent can hold and make your bluffs more credible.
What Is a Blocker?
A blocker is a card in your hand that makes it impossible for the opponent to hold certain combinations. If you have A♠, the opponent cannot have A♠A♥ or A♠K♠.
Blockers for Bluffs
The best river bluffs use hands with blockers on the opponent’s calling range. You want to block the hands that would call you.
A♠ on a spade flush board: blocks the best callers
K♠ on a spade flush board: same effect to a lesser degree
Aces block A♠A♥ and AK in opponent value ranges
Blockers for Value
For value, you want to ‘unblock’ the opponent’s calling range — meaning you want them to have hands that call your bet.
Practical Application
These concepts are most relevant on the river in key spots. Don’t overthink blockers on the flop — focus on fundamentals first.
Unblockers
The reverse of blockers: certain cards in your hand increase the probability that your opponent holds specific combos. Use this to optimize both bluffs and value bets.
